<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Statement
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */

/**
 * @see Zend_Db_Statement
 */
require_once 'Zend/Db/Statement.php';

/**
 * Extends for Microsoft SQL Server Driver for PHP
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Statement
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Db_Statement_Sqlsrv extends Zend_Db_Statement
{

	/**
	 * The connection_stmt object original string.
	 */
	protected $_originalSQL;

	/**
	 * Column names.
	 */
	protected $_keys;

	/**
	 * Query executed
	 */
	protected $_executed = false;

	/**
	 * Prepares statement handle
	 *
	 * @param string $sql
	 * @return void
	 * @throws Zend_Db_Statement_Sqlsrv_Exception
	 */
	protected function _prepare($sql)
	{
		$connection = $this->_adapter->getConnection();

		$this->_stmt = sqlsrv_prepare($connection, $sql);

		if (!$this->_stmt) {
			require_once 'Zend/Db/Statement/Sqlsrv/Exception.php';
			throw new Zend_Db_Statement_Sqlsrv_Exception(sqlsrv_errors());
		}

		$this->_originalSQL = $sql;
	}

	/**
	 * Binds a parameter to the specified variable name.
	 *
	 * @param mixed $parameter Name the parameter, either integer or string.
	 * @param mixed $variable  Reference to PHP variable containing the value.
	 * @param mixed $type      OPTIONAL Datatype of SQL parameter.
	 * @param mixed $length    OPTIONAL Length of SQL parameter.
	 * @param mixed $options   OPTIONAL Other options.
	 * @return bool
	 * @throws Zend_Db_Statement_Exception
	 */
	protected function _bindParam($parameter, &$variable, $type = null, $length = null, $options = null)
	{
		//Sql server doesn't support bind by name
		return true;
	}

	/**
	 * Closes the cursor, allowing the statement to be executed again.
	 *
	 * @return bool
	 */
	public function closeCursor()
	{
		if (!$this->_stmt) {
			return false;
		}

		sqlsrv_free_stmt($this->_stmt);
		$this->_stmt = false;
		return true;
	}

	/**
	 * Returns the number of columns in the result set.
	 * Returns null if the statement has no result set metadata.
	 *
	 * @return int The number of columns.
	 */
	public function columnCount()
	{
		if ($this->_stmt && $this->_executed) {
			return sqlsrv_num_fields($this->_stmt);
		}

		return 0;
	}


	/**
	 * Retrieves the error code, if any, associated with the last operation on
	 * the statement handle.
	 *
	 * @return string error code.
	 */
	public function errorCode()
	{
		if (!$this->_stmt) {
			return false;
		}

		$error = sqlsrv_errors();
		if (!$error) {
			return false;
		}

		return $error[0]['code'];
	}


	/**
	 * Retrieves an array of error information, if any, associated with the
	 * last operation on the statement handle.
	 *
	 * @return array
	 */
	public function errorInfo()
	{
		if (!$this->_stmt) {
			return false;
		}

		$error = sqlsrv_errors();
		if (!$error) {
			return false;
		}

		return array(
		$error[0]['code'],
		$error[0]['message'],
		);
	}


	/**
	 * Executes a prepared statement.
	 *
	 * @param array $params OPTIONAL Values to bind to parameter placeholders.
	 * @return bool
	 * @throws Zend_Db_Statement_Exception
	 */
	public function _execute(array $params = null)
	{
		$connection = $this->_adapter->getConnection();
		if (!$this->_stmt) {
			return false;
		}

		if ($params !== null) {
			if (!is_array($params)) {
				$params = array($params);
			}
			$error = false;

			// make all params passed by reference
			$params_ = array();
			$temp    = array();
			$i       = 1;
			foreach ($params as $param) {
				$temp[$i]  = $param;
				$params_[] = &$temp[$i];
				$i++;
			}
			$params = $params_;
		}

		$this->_stmt = sqlsrv_query($connection, $this->_originalSQL, $params);

		if (!$this->_stmt) {
			require_once 'Zend/Db/Statement/Sqlsrv/Exception.php';
			throw new Zend_Db_Statement_Sqlsrv_Exception(sqlsrv_errors());
		}

		$this->_executed = true;

		return (!$this->_stmt);
	}

	/**
	 * Fetches a row from the result set.
	 *
	 * @param  int $style  OPTIONAL Fetch mode for this fetch operation.
	 * @param  int $cursor OPTIONAL Absolute, relative, or other.
	 * @param  int $offset OPTIONAL Number for absolute or relative cursors.
	 * @return mixed Array, object, or scalar depending on fetch mode.
	 * @throws Zend_Db_Statement_Exception
	 */
	public function fetch($style = null, $cursor = null, $offset = null)
	{
		if (!$this->_stmt) {
			return false;
		}

		if (null === $style) {
			$style = $this->_fetchMode;
		}

		$values = sqlsrv_fetch_array($this->_stmt, SQLSRV_FETCH_ASSOC);

		if (!$values && (null !== $error = sqlsrv_errors())) {
			require_once 'Zend/Db/Statement/Sqlsrv/Exception.php';
			throw new Zend_Db_Statement_Sqlsrv_Exception($error);
		}

		if (null === $values) {
			return null;
		}

		if (!$this->_keys) {
			foreach ($values as $key => $value) {
				$this->_keys[] = $this->_adapter->foldCase($key);
			}
		}

		$values = array_values($values);

		$row = false;
		switch ($style) {
			case Zend_Db::FETCH_NUM:
				$row = $values;
				break;
			case Zend_Db::FETCH_ASSOC:
				$row = array_combine($this->_keys, $values);
				break;
			case Zend_Db::FETCH_BOTH:
				$assoc = array_combine($this->_keys, $values);
				$row   = array_merge($values, $assoc);
				break;
			case Zend_Db::FETCH_OBJ:
				$row = (object) array_combine($this->_keys, $values);
				break;
			case Zend_Db::FETCH_BOUND:
				$assoc = array_combine($this->_keys, $values);
				$row   = array_merge($values, $assoc);
				$row   = $this->_fetchBound($row);
				break;
			default:
				require_once 'Zend/Db/Statement/Sqlsrv/Exception.php';
				throw new Zend_Db_Statement_Sqlsrv_Exception("Invalid fetch mode '$style' specified");
				break;
		}

		return $row;
	}

	/**
	 * Returns a single column from the next row of a result set.
	 *
	 * @param int $col OPTIONAL Position of the column to fetch.
	 * @return string
	 * @throws Zend_Db_Statement_Exception
	 */
	public function fetchColumn($col = 0)
	{
		if (!$this->_stmt) {
			return false;
		}

		if (!sqlsrv_fetch($this->_stmt)) {
			if (null !== $error = sqlsrv_errors()) {
				require_once 'Zend/Db/Statement/Sqlsrv/Exception.php';
				throw new Zend_Db_Statement_Sqlsrv_Exception($error);
			}

			// If no error, there is simply no record
			return false;
		}

		$data = sqlsrv_get_field($this->_stmt, $col); //0-based
		if ($data === false) {
			require_once 'Zend/Db/Statement/Sqlsrv/Exception.php';
			throw new Zend_Db_Statement_Sqlsrv_Exception(sqlsrv_errors());
		}

		return $data;
	}

	/**
	 * Fetches the next row and returns it as an object.
	 *
	 * @param string $class  OPTIONAL Name of the class to create.
	 * @param array  $config OPTIONAL Constructor arguments for the class.
	 * @return mixed One object instance of the specified class.
	 * @throws Zend_Db_Statement_Exception
	 */
	public function fetchObject($class = 'stdClass', array $config = array())
	{
		if (!$this->_stmt) {
			return false;
		}

		$obj = sqlsrv_fetch_object($this->_stmt);

		if ($error = sqlsrv_errors()) {
			require_once 'Zend/Db/Statement/Sqlsrv/Exception.php';
			throw new Zend_Db_Statement_Sqlsrv_Exception($error);
		}

		/* @todo XXX handle parameters */

		if (null === $obj) {
			return false;
		}

		return $obj;
	}

	/**
	 * Returns metadata for a column in a result set.
	 *
	 * @param int $column
	 * @return mixed
	 * @throws Zend_Db_Statement_Sqlsrv_Exception
	 */
	public function getColumnMeta($column)
	{
		$fields = sqlsrv_field_metadata($this->_stmt);

		if (!$fields) {
			throw new Zend_Db_Statement_Sqlsrv_Exception('Column metadata can not be fetched');
		}

		if (!isset($fields[$column])) {
			throw new Zend_Db_Statement_Sqlsrv_Exception('Column index does not exist in statement');
		}

		return $fields[$column];
	}

	/**
	 * Retrieves the next rowset (result set) for a SQL statement that has
	 * multiple result sets.  An example is a stored procedure that returns
	 * the results of multiple queries.
	 *
	 * @return bool
	 * @throws Zend_Db_Statement_Exception
	 */
	public function nextRowset()
	{
		if (sqlsrv_next_result($this->_stmt) === false) {
			require_once 'Zend/Db/Statement/Sqlsrv/Exception.php';
			throw new Zend_Db_Statement_Sqlsrv_Exception(sqlsrv_errors());
		}

		//else - moved to next (or there are no more rows)
	}

	/**
	 * Returns the number of rows affected by the execution of the
	 * last INSERT, DELETE, or UPDATE statement executed by this
	 * statement object.
	 *
	 * @return int     The number of rows affected.
	 * @throws Zend_Db_Statement_Exception
	 */
	public function rowCount()
	{
		if (!$this->_stmt) {
			return false;
		}

		if (!$this->_executed) {
			return 0;
		}

		$num_rows = sqlsrv_rows_affected($this->_stmt);

		// Strict check is necessary; 0 is a valid return value
		if ($num_rows === false) {
			require_once 'Zend/Db/Statement/Sqlsrv/Exception.php';
			throw new Zend_Db_Statement_Sqlsrv_Exception(sqlsrv_errors());
		}

		return $num_rows;
	}
}
